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Dietary Restriction for Recurrent
Nephrolithiasis
Iris Thiele Isip Tan MD, FPCP, FPSEMClinical Associate Professor, UP College of Medicine
Section of Endocrinology, Diabetes & MetabolismDepartment of Medicine, Philippine General Hospital
Increase fluid intake to ensure a urine volume of at least 2 liters/day
pH < 5.5 pH > 6.0
Calcium >170 mg/L
♀>250 mg/24h ♂>300 mg/24h
Oxalate >40 mg/24 h
Citrate <350 mg/24 h
Phytate <1 mg/24h
Urate >650 mg/L
♀>600 mg/24h ♂>800 mg/24h
Grases et al, Nutrition Journal 2006;5:23
Urinary Lithogen Factors
pH < 5.5
Calcium oxalate
Uric acid
Cystine
Calcium oxalate/uric acid mixed
Animal protein
Citrus juicesSoftdrinks
Citric acid rich
beverages
Grases et al, Nutrition Journal 2006;5:23
pH > 6
Vegetarian dietCitrus juicesSoftdrinks
Citric acid rich beverages
Grases et al, Nutrition Journal 2006;5:23
Calcium oxalate
Hydroxyapatite
Brushite
Calcium oxalate/Hydroxyapatite
mixed
Oxalate >40 mg/24h
Oxalate rich foodsAscorbic acid rich foods
(vit C intake >2 g/day)
Grases et al, Nutrition Journal 2006;5:23
Calcium oxalate
Spinach RhubarbPurslane ParsleySweet potatoesLambsquarters
ChivesBeet leavesAmaranth OkraGreen teaChocolate
SodiumAnimal protein
Water intake >2 li/day
Grases et al, Nutrition Journal 2006;5:23
Calcium >170 mg/L♀>250 mg/24h ♂>300 mg/24h
Calcium oxalate
Calcium oxalate/Hydroxyapatite
mixed
Hydroxyapatite
Control vit D consumption
& calcium supplements
Avoid Ca restriction in hypercalciuric patients
❖ No clear distinction between absorptive and renal hypercalciuria
❖ No prospective studies to support belief that calcium restriction leads to reduction in stone recurrence
❖ Calcium restriction induces secondary hyperoxaluria
Heilberg I. Nephrol Dial Transplant 2000;15:117-123
Avoid Ca restriction in hypercalciuric patients
❖ Predisposes to bone loss (negative calcium balance)
❖ Chronic Ca restriction might upregulate vitamin D receptors (stimulate intestinal Ca absorption and bone resorption)
❖ Other nutrients (protein, Na, oxalate and K) affect calcium excretion
Heilberg I. Nephrol Dial Transplant 2000;15:117-123
Comparison of two diets for the prevention of recurrent stones in idiopathic hypercalciuria
Borghi et al, NEJM 2002:346:77-84
low Ca dietn = 60
normal Ca, low animal protein, low salt diet
n = 60
Recurrent calcium oxalate stones with idiopathic hypercalciuria (Italy)
5-year follow-up
Avoid milk, yoghurt & cheese to reduce Ca intake 10 mmol/dayAvoid oxalate-rich foods (walnuts, spinach, rhubarb, parsley, chocolate)
TCR: 2540 kcalTotal protein: 15% Lipids: 33% CHO: 52%Ca: 30 mmol/dayNaCl: 50 mmol/dayAvoid oxalate-rich foods
Both diets allowed 2-3 liters of water/day
Comparison of two diets for the prevention of recurrent stones in idiopathic hypercalciuria
Borghi et al, NEJM 2002:346:77-84
Primary outcome measure:Time to first recurrence of symptomatic renal stone* or presence of radiographically identified stone**
* Typical renal colic, episode of hematuria, expulsion or removal of previously undiscovered stone ** Renal UTZ/abdominal flat plate yearly
low Ca dietn = 60
normal Ca, low animal protein, low salt diet
n = 60
23/60 had relapses⬇Urinary Ca
⬆Urinary oxalate
(5.4 mg/d or 60 umol/d)
12/60 had relapses⬇Urinary Ca
⬇Urinary oxalate
(7.2 mg/d or 80 umol/d)
Comparison of two diets: cumulative incidence of recurrence (%)
Borghi et al, NEJM 2002:346:77-84
0
50
0 60
40
30
20
10
6 12 18 24 30 36 42 48 54
Month
Low calcium
Normal calcium, low protein, low salt
Cum
ulat
ive
Inci
denc
e
of R
ecur
renc
e (%
)
NO. AT RISK
Low calciumNormal calcium, low protein, low salt
6060
5957
5153
4947
4646
4445
4244
3943
3341
3140
2840
Low calcium
Normal calcium, low protein, low salt
RR = 0.49 (95%CI 0.24-0.98), p=0.04
Delayed effect of intervention due to early recurrences in the highest-risk patients
Borghi et al, NEJM 2002:346:77-84
0
80
0 60
70
60
50
40
30
20
10
6 12 18 24 30 36 42 48 54
Month
Low-calcium diet — men at highest risk (n=9)Normal-calcium, low-protein, low-salt diet — men at highest risk (n=14)Low-calcium diet — other men (n=51)Normal-calcium, low-protein, low-salt diet — other men (n=46)
Cum
ulat
ive
Inci
denc
e of
Rec
urre
nce
(%)
High-risk: >5 colic episodes in the year before randomization, >10 stones before randomization or both
Citrate < 350 mg/24 h
Citrate-rich foodsCitric acid rich
beverages
Grases et al, Nutrition Journal 2006;5:23
Calcium oxalate
Hydroxyapatite
Calcium oxalate/Hydroxyapatite
mixed
Phytate < 1 mg/24 h
Phytate rich foods
Cereal germ i.e. corn germ
Cereal bran i.e. wheat cereal (100% bran)
Whole cereals i.e. wild rice
Beans i.e. whole bean, bean flour, tofu
Nuts i.e. brazil nuts
Grases et al, Nutrition Journal 2006;5:23
Calcium oxalate
Brushite
Purine rich foodsAlcoholic drinks
Grases et al, Nutrition Journal 2006;5:23
Uric acid
Calcium oxalate/uric acid mixed
Urate >650 mg/L
♀>600 mg/24h ♂>800 mg/24h
SeafoodCanned seafood (anchovies, sardines in oil, herrings)Fish roeMeatOrgan meat (liver, kidney, sweetbreads)Meat extracts, consomme, gravies
General Dietary Recommendations
❖ Daily intake of a suitable liquid volume (minimum 2 L water/day)
❖ Avoid strictly vegetarian diets
❖ Avoid excessive animal protein diets
Grases et al, Nutrition Journal 2006;5:23
High Protein Intake
Hyperuricosuria (purine overload)
Hyperoxaluria(↑ oxalate synthesis)
Hypocitraturia(↑ tubular citrate
reabsorption)
Hypercalciuria
↑ bone resorption
↓ tubular Ca reabsorption
↑ Ca filtered load
Heilberg I, Arq Bras Endocrinol Metab 2006;50:823-31
General Dietary Recommendations
❖ Avoid excessive salt (NaCl) consumption
❖ Avoid excessive vitamin C and/or vitamin D consumption
❖ Consume phytate-rich products (natural dietary bran, legumes and beans, whole cereals)
Grases et al, Nutrition Journal 2006;5:23
Thank Youhttp://www.endocrine-witch.info